Battery module testing

ABSTRACT

Testing of a battery module can be conducted using monitoring electronics attached to the battery module. Stimulus can be applied to the battery module and removed. After removal of the stimulus, the monitoring electronics can collect signals from the monitoring electronics reflecting parameters of the battery module as it relaxes back to a non-stimulated state. The stimulus can be provided by test equipment or by components of a system in which the battery module, having attached monitoring electronics, is implemented. The monitoring electronics attached to the battery module can provide autonomous recording of signals associated with the battery module that can provide data regarding the status of the battery module or one or more batteries contained in the battery module.

PRIORITY APPLICATIONS

This application is a Continuation in Part application of U.S. patent application Ser. No. 17/021,682 filed 15 Sep. 2020, which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 62/994,652 filed 25 Mar. 2020, both of which are incorporated herein by reference in their entirety.

FIELD OF THE DISCLOSURE

This document relates to measurement apparatus and methods and, in particular, to battery measurement apparatus and methods.

BACKGROUND

Electrical impedance spectroscopy (EIS) is a measurement of electrochemical impedance. Electrochemical impedance is usually measured by applying an AC (alternating current) signal, such as a sinusoidal test voltage or current, to an electrochemical cell under test and then measuring the current through the electrochemical cell. EIS uses measurement of impedance over a suitable frequency range. This can provide a useful technique to investigate the electrical properties of a large variety of materials and devices such as batteries.

With batteries placed in a module, which can subsequently be placed as power sources in apparatus, EIS testing after module creation is typically not executed today. In conventional procedures to weed out bad battery units, battery module voltage is measured, the battery module is stored for a number of weeks, and then battery voltage is remeasured. If the drop in voltage is abnormal, the battery is omitted. Advances in techniques of battery measurement can enhance battery technology and its application.

SUMMARY OF THE DISCLOSURE

A device having a structure to measure one or more parameters of a battery module or one or more batteries of the battery module can be implemented in a variety of applications. Testing of a battery module can be conducted using monitoring electronics attached to the battery module, with a stimulus applied to the battery module and removed. After removal of the stimulus, the monitoring electronics can collect signals from the monitoring electronics reflecting parameters of the battery module as it relaxes back to a non-stimulated state. The stimulus can be provided by test equipment or by components of a system in which the battery module, having attached monitoring electronics, is implemented. The monitoring electronics attached to the battery module can provide autonomous recording of signals associated with the battery module that can provide data regarding the status of the battery module or one or more batteries contained in the battery module.

In certain embodiments, a method of battery testing can be provided that discloses: applying a stimulus to a battery module, the battery module having one or more batteries; turning off use of the battery module including removing the stimulus to the battery module; after turning off use of the battery module, autonomously recording signals from the battery module during a post-stimulus battery relaxation period using monitoring electronics attached to the battery module; and outputting the recorded signals from which one or more electrochemical parameters, electro-mechanical parameters; or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.

In certain embodiments, a system can be provided that discloses a battery module having one or more batteries; monitoring electronics attached to the battery module, the monitoring electronics to monitor response of a battery of the battery module to a stimulus applied to the battery; and a controller. The controller is configured to perform operations that include turning off use of the battery module including removing the stimulus to the battery module; after removing the stimulus to the battery module, timing a post-stimulus battery relaxation period and autonomously recording signals from the battery module during the post-stimulus battery relaxation period using the monitoring electronics; and outputting the recorded signals from which one or more electrochemical parameters. One or more electromechanical parameters, or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.

In certain embodiments, an electric vehicle can be provided that discloses: a battery module having one or more batteries to power the electric vehicle; monitoring electronics attached to the battery module, the monitoring electronics to monitor response of a battery of the battery module to a stimulus applied to the battery; and a controller. The controller is configured to perform operations including turning off use of the battery module including removing the stimulus to the battery module; after removing the stimulus to the battery module, timing a post-stimulus battery relaxation period and autonomously recording signals from the battery module during the post-stimulus battery relaxation period using the monitoring electronics; and outputting the recorded signals from which one or more electrochemical parameters, electro-mechanical parameters, or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed herein. The drawings are not necessarily drawn to scale.

FIGS. 1-6 illustrate a flow of an example method of battery module testing using battery test equipment as stimulus and autonomous recording of measurement signals via electronics attached to the battery module, in accordance with various embodiments.

FIG. 7 illustrates an example battery pack in a car, in accordance with various embodiments.

FIG. 8 is a flow diagram of features of an example method of battery testing, in accordance with various embodiments.

FIG. 9 is a block diagram of features of an example system having battery modules with monitoring electronics attached to the battery modules, in accordance with various embodiments.

DETAILED DESCRIPTION

In various embodiments, battery module EIS measurement can be realized using battery test equipment as stimulus and autonomous recording of voltage via electronics attached to the module. This measurement method can execute EIS analysis of the battery by the combination of battery test equipment and autonomous battery monitoring. The use of autonomous measurement allows the battery to be tested at high volume quickly, then moved to storage where the monitoring can continue for a relatively long period.

An example measurement procedure on a battery module can be conducted in the following manner. Stimulus to the battery module can be applied via test equipment. Such test equipment can include, but is not limited to, battery module end of line test equipment. After completion of the application of the stimulus, the battery module is removed from the test equipment. Using electronics attached to the battery module, one or more of voltage, temperature, and impedance is recorded autonomously. The electronics can measure the battery module periodically to save energy. The measurement electronics can be powered by the battery module. The known stimulus and the recorded parameters can be used to calculate electrochemical parameters, electro-mechanical parameters, or other parameters of the battery module or one or more of the batteries.

In various embodiments, autonomous measurement of the battery module is made in reaction to a stimulus provided by test equipment. The autonomous measurement can be conducted after the stimulus is applied and after removal from being coupled to the test equipment. This is a superior procedure to conventional use of test equipment to measure battery parameters, as the battery reaction to the stimulus typically requires a long settling time. It is not efficient to hold the test equipment to a given battery module during the settling time. For example, for an automotive assembly line for electric vehicle battery modules, test time should be very short. Autonomous measurement, as taught herein, allows the measurement to continue offline, freeing up the equipment. Other assembly lines can be implemented in a similar manner for battery modules for other apparatus having a battery-based electric function. A vehicle can include, but is not limited to, a truck, a bus, a ship, an airplane, a bike, a robot, a train, or other instrumentality that moves as part of its function.

FIGS. 1-6 illustrate an embodiment of a flow of an example method of battery module testing using battery test equipment to provide stimulus and autonomous recording of measurement signals via electronics attached to the battery module. The battery module testing can include electrochemical impedance spectroscopy measurement. FIG. 1 illustrates a point in the manufacture flow at which one or more battery cells 105-1, 105-2, 105-3, and 105-4 are formed into a battery module 110. Battery modules can contain more or less than four battery cells.

FIG. 2 illustrates a point in the manufacture flow at which cell monitoring electronics 115 are added to battery module 110 to form a battery module 120 having monitoring electronics. The monitoring electronics 115 are electrically coupled to the battery module 110 and the one or more battery cells 105-1, 105-2, 105-3, and 105-4 to make measurements of these structures. The monitoring electronics 115 can include a wireless communication device 116 to transmit data measured or signals collected by the monitoring electronics 115. The measured data or the collected signals can be sent to a device or system exterior to the battery module 120. Monitoring electronics 115 can be implemented as one or more cell monitoring electronic units attachable to the one or more battery cells 105-1, 105-2, 105-3, and 105-4 formed into a battery module 110. In this example method, the cell monitoring electronics is capable of autonomously measuring some electrical parameters of the battery module 120 having monitoring electronics, or the one or more battery cells 105-1, 105-2, 105-3, and 105-4. For example, battery cell voltage, temperature, or impedance can be measured.

FIG. 3 illustrates a point in the manufacture flow at which the battery module 120 having monitoring electronics is stimulated by manufacturing test equipment 125. The manufacturing test equipment 125 can be high-volume manufacturing test equipment. Standard manufacturing test equipment can be used to provide the stimulus. The battery module 120 having monitoring electronics can be charged and/or discharged at least once. This stimulation by the manufacturing test equipment is known, measured, or can be inferred.

FIG. 4 illustrates a point in the manufacturing method at which the applied stimulus is removed from the battery module 120 having monitoring electronics. At this point, the monitoring electronics 115 autonomously records battery electrical signals. For example, this autonomous measurement can be made during transport or storage of the battery module 120 having monitoring electronics. Such transport or storage can be separate from inclusion in an application apparatus.

Because of the application of the stimulus, the battery module 120 having monitoring electronics has been excited and can take several hours to relax back to its natural state. The monitoring electronics 115, during the relaxation period, can keep measuring electrical parameters of the battery module 120 autonomously and keep recording signals from which these electrical parameters are derived. The battery module 120 can be shipped to a warehouse, with the cell monitoring electronics 115 continuing to carry out these autonomous measurements until the battery is completely or substantially relaxed, which could take, for example, 12 to 24 hours or longer. The autonomous measurements can be controlled by one or more processing devices and memory contained within monitoring electronics 115. The monitoring electronics 115 can be capable of measuring individual batteries of the battery module 120.

FIG. 5 illustrates a point in the method at which the recorded signals in the monitoring electronics 115 can be transmitted to a receiving device wirelessly or retrieved from memory of the monitoring electronics 115 later. The receiving device can be a local information technology (IT) system or a non-local IT system 130 such as, but not limited to, a cloud-based IT system. The IT systems can include data processing systems, information systems, recordkeeping systems, communications systems, telecommunications systems, account management systems, inventory management systems, other processing-based systems, and Internet websites, all which can be electronic or opto-electronic based systems. Such systems include associated computer programs, software, databases, firmware, hardware, and related documentation. The wireless transmission can be conducted using any one of a number of wireless transmission protocols. In some embodiments, the wireless communication can be conducted using a transmission protocol suited for a range of 5 to 10 meters. However, the wireless transmission is not limited to a range of 5 to 10 meters. In some embodiments in which data is retrieved from the memory of the monitoring electronics at a later time, the data transmission can be made via wired connections such as, but not limited to, universal serial bus (USB) connections. Short range wireless communications and USB connections can be coupled to one or more communications networks, which can include a local area network (LAN) or a wide area network (WAN).

FIG. 6 illustrates a point in the method at which EIS characteristics of the battery module 120 or one or more battery cells of the battery module 120 are calculated at the local IT system or the non-local IT system 130 providing an analysis 135. The characteristics can be EIS characteristics. Such calculations can be based on the recorded data by the monitoring electronics 115, as illustrated in FIG. 4 , and known stimulus provided from test equipment 125, as illustrated in FIG. 3 . The stimulus and the relaxation of the battery module 120 provides some of the electrochemical parameters of the battery module 120. The measured reaction to the stimulus over the relaxation time period allows the EIS parameters of the battery module 120 to be modeled in the analysis 135 in the IT system 130. These parameters and modelling can be conducted on an individual battery basis in addition to the modeling of the battery module 120 as a single unit. During the measurement over the relaxation period, the stimulus of the manufacturing test equipment 120 is not being provided to the battery module. In some embodiments, a portion of the analysis of the measurement data can be conducted in the monitoring electronics 115.

The process taught in FIGS. 1-6 includes measuring properties of a battery module or one or more batteries in the battery module by applying a stimulus to the battery module and measuring signals from the battery module after the stimulus has been removed with the battery module in a state in which it is not being actively used. The measuring signals can be collected before the batteries of the battery module relax to a relaxed state, where a normal relaxed state is associated with battery module not in use. The measured battery module can be stored for later use in various applications.

A similar process can be used in a variety of applications, where a battery module is stimulated, and electrical signals are collected from the battery module with the stimulus removed and the battery module not being actively used in the application. In these applications, the stimulus can be provided by monitoring electronics using a small amount of power from the battery module with the respective application not using the battery module. In some applications having multiple battery modules, one battery module can be tested with stimulus provided by another one of the battery modules. For example, applications not using the battery module can include an application that has idle periods or periods of being on and off. The off periods of such applications can provide an opportunity to test a battery module or one or more batteries of the battery module as the battery module or the one or more batteries transition through a relaxation period.

FIG. 7 illustrates an embodiment of an example battery pack 219 in a car 240. The car 240 can be an electric car. The battery pack 219 can include a battery module 220-1, a battery module 220-2, a battery module 220-3, a battery module 220-4, a battery module 220-5, a battery module 220-6, a battery module 220-7, and a battery module 220-8. The battery pack 219 can have more or less than eight battery modules. The battery modules 220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8 can be connected in series with terminals HV+ and HV− to provide operating power for the car 240. Each of the battery modules 220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8 can be structured as a battery module having monitoring electronics similar to, but not limited to, the battery module 120 having monitoring electronics of FIG. 4 .

As the car 240 drives, the battery modules 220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8 in the pack 219 are excited. When the car 240 is turned off, monitoring electronics on the battery modules 220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8 can measure battery parameters. Monitoring electronics on the battery modules 220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8 can measure battery parameters even if a BMS (battery management system) controller of the vehicle is turned off or in a state where it is not capable of issuing commands to the monitoring electronic. The monitor electronic can be capable of measuring autonomously. The measured parameters can include such parameters as voltage, temperature, and impedance. Signals for these parameters can also be collected in an automotive BMS system of the car 240. Monitoring electronics on the battery modules 220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8 can send data to an engine control unit (ECU) 250 for the car 240, wirelessly or wired. This data can be sent when the vehicle or the BMS controller is turned on again. An ECU is an internal computer of a car, which monitors and reacts to changes that occur in the systems of the car. Wireless data transfer to the ECU 250 can be implemented using a wireless collector 245. The wireless collector 245 can be connected to the ECU 250 via a wired connection or a wirelessly. In some instances when the car 240 is off, the car ECU 250 can be woken up by the monitoring electronics of one or more of the battery modules 220-1, 220-2, 220-3, 220-4, 220-5, 220-6, 220-7, and 220-8 or by the wireless collector 245. The data can be processed in the car 240 or sent to a cloud 260 for processing. The data can be stored in the BMS of the car 240 for access at a later date, such as at a standard maintenance inspection.

Typically, the term “cloud” with respect to data processing and communicating refers to a datacenter full of servers that is connected to the Internet. However, cloud may refer to any network or combinations of networks. A cloud can include a wide area network (WAN) like the public Internet or a private, national or global network, and may include a local area network (LAN) within an organization providing the services of the datacenter. In addition, the term “cloud computing” refers to the software and services executed for users by these servers, and typically the user is unaware of the physical location of the servers or datacenter. Further, the datacenter may be a distributed entity. Cloud computing can provide shared computer processing resources and data to computers and other devices on demand over associated networks.

EIS analysis can include processing of the data collected by the monitoring electronics of a battery module to detect an anomaly. An anomaly for a battery module can be data for a battery of the battery module that is different from data for the other batteries of the battery module. An anomaly for a battery module can be data of a parameter that differs significantly from past data of the parameter for the battery module. An anomaly can be a reaction, by the battery module or one or more batteries of the battery module to the stimulus, that is abnormal.

EIS analysis can include processing of the data collected by the monitoring electronics of a battery module to determine hidden states of the battery module, state of charge (SOC), and a state of health (SOH) of the battery module. The EIS analysis can be applied to small and large battery modules, such as but not limited to, for example, large battery modules or groups of large battery modules used in electric vehicles. Hidden states of the battery are states that are difficult to measure directly. The hidden states can be determined based on the measured data and a database that converts observable data to hidden states. Measurements and determined hidden states with respect to voltage and temperature can be used in one or more algorithms to calculate SOC and SOH, and to evaluate whether or not the batteries and battery modules are at a safe operating temperature.

EIS analysis can include processing of the data collected by the monitoring electronics of a battery module to model the battery module or one or more batteries of the battery module based on the observed data collected by the monitoring electronics of the battery module. The modelling can include creating a small signal electrical model. The electrical model can be interrogated to generate relevant impedances. Hidden states of the battery, SOC, and SOH can be determined based on the generated impedances and a database, where the database can be used to convert one or more impedances to hidden states.

The processed data collected by the monitoring electronics of a battery module can be used in a number of different ways. The processed data can be used to provide an alert regarding battery degradation and to characterize battery health. For example, with battery modules having monitoring electronics used in a car, as discussed with respect to FIG. 7 , in response to a determination of battery degradation, an alert of the battery degradation can be generated on a display within the car. The characterization of the health of the battery module or its batteries can also be generated on a display within the car. Display of battery degradation and health can be used in applications other than in a car.

The processed data can be used to in a manufacturing application. In response to a determination that one or more battery modules have an anomaly, an anomalous battery module can be removed from a supply chain. The processed data can be used in an inventory system to grade and sort the battery modules based on processing the data from battery testing as taught herein.

FIG. 8 is a flow diagram of features of an embodiment of an example method 800 of battery testing. At 810, a stimulus is applied to a battery module, where the battery module has one or more batteries. At 820, use of the battery module is turned off, including removing the stimulus to the battery module. At 830, after turning off use of and removing the stimulus to the battery module, signals from the battery module are autonomously recorded using monitoring electronics attached to the battery module. Autonomously recording the signals from the battery module can include recording voltage, temperature, or impedance of the battery module or the one or more batteries. The signals from the battery module can be autonomously recorded during a period including from turning off use of and removing the stimulus to the battery module to completion or substantial completion of relaxation of the battery module from applying the stimulus. The autonomous recording of the signals can be conducted continuously or periodically during this period. The completion of the relaxation of the battery module from applying the stimulus can be the turning on of a next use of the battery module, such as for example in a car or other apparatus that operates with period of on and off. Monitoring signals can also be collected during use of the battery module.

At 840, the recorded signals are output, from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals. The recorded signals can be transmitted wirelessly to a receiving device to analyze data from the recorded signals. The one or more electrochemical parameters or the one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module can be calculated using a processing device coupled to the receiving device. Alternatively, this calculation can be conducted in conjunction with the monitoring electronics. Electrochemical Impedance Spectroscopy characteristics of the battery module or the one or more of the batteries can be calculated based on data from the recorded signals and the stimulus.

Variations of method 800 or methods similar to the method 800 can include a number of different embodiments that may be combined depending on the application of such methods and/or the architecture of systems in which such methods are implemented. Such methods can comprise applying the stimulus to the battery module to include applying the stimulus to the battery module using test equipment; and turning off use of the battery module including removing the stimulus to the battery module from the test equipment. The one or more batteries can be formed into the battery module before applying the stimulus to the battery module or to the one or more batteries. Applying the stimulus to the battery module using the test equipment can include charging and discharging the one or more batteries of the battery module. Signals from the battery module can be autonomously recorded during a period including from removal of the battery module from coupling to the test equipment to completion or substantial completion of relaxation of the battery module from applying the stimulus. The recorded signals can be retrieved from memory of the monitoring electronics at a time after removal from coupling to test equipment and after the battery module has relaxed from the applied stimulus. The recorded signals can be retrieved from the monitoring electronics and wirelessly transmitted to analysis apparatus.

Variations of method 800 or methods similar to the method 800 can comprise applying the stimulus to the battery module to include exciting the battery module with the battery module operable in a car, with the exciting enabled with the car in an on-status; and turning off use of the battery module including removing the stimulus to the battery module with the turning off of the car. Method 800 or methods similar to the method 800 can be applied to other apparatus that operate on battery power, where the apparatus goes through periods of being on and off. These on and off periods allow testing of a battery module or individual battery during a relaxation period after the stimulus of being on is removed.

Variations of method 800 or methods similar to the method 800 can include detecting an anomaly from the recorded signals; or determining a hidden state of the battery module or one or more of the batteries based on the recorded signals and a database that converts observable data to hidden states. Variations can include modelling the battery module or one or more of the batteries based on the recorded signals, including creating an electrical model; interrogating the electrical model; generating impedances from the interrogating of the electrical model; and determining a hidden state of the battery module or one or more of the batteries, based on the generated impedances and a database that converts impedances to hidden states.

Variations of method 800 or methods similar to the method 800 can include processing the recorded signal to provide, to a display, a characterization of health of the battery. In response to a determination of battery degradation, the processing can include generating an alert of the battery degradation. Variations can include processing the recorded signals, to provide, to a display, a quality grade of the battery module. In response to a determination of an anomaly associated with the battery module, an identification of the battery module being an anomalous battery module can be generated.

In various embodiments, a non-transitory machine-readable storage device, such as a computer-readable non-transitory medium, can comprise instructions stored thereon, which, when performed by a machine, cause the machine to perform operations, where the operations comprise one or more features similar to or identical to features of methods and techniques described with respect to method 800, variations thereof, and/or features of other methods or functions taught herein such as associated with FIGS. 1-9 . The physical structures of such instructions may be operated on by one or more processors. Executing these physical structures can cause the machine to perform a variety of operations.

A non-transitory machine-readable medium storing instructions for testing a battery module, that when executed by one or more processors, can cause a system to perform operations comprising: applying a stimulus to a battery module, the battery module having one or more batteries; turning off use of the battery module including removing the stimulus to the battery module; after turning off use of and removing the stimulus to the battery module, autonomously recording signals from the battery module using monitoring electronics attached to the battery module; and outputting the recorded signals from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals. The operations can include controlling application of the stimulus to the battery module using test equipment and turning off use of the battery module and removing the stimulus to the battery module by removing the stimulus from and communication with the test equipment. The operations can include recording voltage, temperature, or impedance of the one or more batteries. The operations can include autonomously recording the signals from the battery module during a period including from turning off use of and removing the stimulus to the battery module to completion of relaxation of the battery module from applying the stimulus.

The instructions can be executed by the one or more processors to perform operations to transmit the recorded signals wirelessly to a receiving device to analyze data from the recorded signals. The operations can also include retrieving the recorded signals from memory of the monitoring electronics at a time after removal from coupling to test equipment providing the stimulus and after the battery module has relaxed from the applied stimulus. The operations can include calculating Electrochemical Impedance Spectroscopy characteristics of the battery module or the one or more of the batteries based on data from the recorded signals and the stimulus.

Variations of the operations executable by the one or more processors can include a number of different embodiments that may be combined depending on the application of such non-transitory machine-readable storage devices and/or the architecture of systems in which such non-transitory machine-readable storage device are implemented. Such operations can include applying the stimulus to the battery module to excite the battery module with the battery module operable in a car, with the exciting enabled with the car in an on-status; and turning off use of the battery module including removing the stimulus to the battery module with the turning off of the car. Variations of the operations executable by the one or more processors can be applied to other apparatus that operate on battery power, where the apparatus goes through periods of being on and off. These on and off periods allow testing of a battery module or individual battery during a relaxation period after the stimulus of being on is removed.

Variations of the operations can include detecting an anomaly from the recorded signals or determining a hidden state of the battery module or one or more of the batteries based on the recorded signals and a database that converts observable data to hidden states. Variations of the operations can include modelling the battery module or one or more of the batteries based on the recorded signals, including creating an electrical model; interrogating the electrical model; generating impedances from the interrogating of the electrical model; and determining a hidden state of the battery module or one or more of the batteries, based on the generated impedances and a database that converts impedances to hidden states.

In various embodiments, a system can comprise: a battery module having one or more batteries; monitoring electronics attached to the battery module, the monitoring electronics to monitor response of a battery of the battery module to a stimulus applied to the battery; and a controller configured to perform operations. The operations can include: turning off use of the battery module including removing the stimulus to the battery module; after turning off use of and removing the stimulus to the battery module, autonomously recording signals from the battery module using the monitoring electronics; and outputting the recorded signals from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.

Variations of such a system can include a number of different embodiments that may be combined depending on the application of such systems and/or the architecture in which such systems are implemented. Such systems can include test equipment to provide the stimulus to the battery. The signals autonomously recorded signals can be voltage, temperature, or impedance of the one or more batteries. Such systems can include a transmitter to transmit the recorded signals wirelessly to a receiving device to analyze data from the recorded signals.

Variations of such systems can include the controller being operable to autonomously record signals from the battery module during a period including from turning off use of and removing the stimulus to the battery module to completion of relaxation of the battery module from applying the stimulus. Such systems can include a processing device configured to perform operations, where the operations include: modelling the battery module or one or more of the batteries based on the recorded signals, including creating an electrical model; interrogating the electrical model; generating impedances from the interrogating of the electrical model; and determining a hidden state of the battery module or one or more of the batteries, based on the generated impedances and a database that converts impedances to hidden states. Such systems can be implemented to perform the functions of methods and techniques described with respect to method 800, variations thereof, methods similar to method 800, and/or features of other methods or functions taught herein.

In various embodiments, a system can comprise: a battery module having one or more batteries; a means to monitor a response of a battery of the battery module to a stimulus applied to the battery; a means to autonomously record signals from the battery module in response to the means to monitor the response of the battery identifying the turning off of the battery module including removal of the stimulus to the battery; and a means to output the recorded signals from which one or more electrochemical parameters. Electro-mechanical parametersm or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals. Autonomously recording the signals from the battery module can occur during a period including from turning off use of and removing the stimulus to the battery to completion of relaxation of the battery from applying the stimulus.

Variations of such a system can include a number of different embodiments that may be combined depending on the application of such systems and/or the architecture in which such systems are implemented. Such systems can include a means to process the recorded signals, with the means to process the recorded signals being operable to provide, to a display, a characterization of health of the battery including, in response to a determination of battery degradation, an alert of the battery degradation. Variations of such systems can include a means to process the recorded signals, with the means to process the recorded signals being operable to provide, to a display, a quality grade of the battery module including, in response to a determination of an anomaly associated with the battery module, an identification of the battery module being an anomalous battery module. Such systems can be implemented to perform the functions of methods and techniques described with respect to method 800, variations thereof, methods similar to method 800, and/or features of other methods or functions taught herein.

FIG. 9 is a block diagram of features of an embodiment of an example system 900 having battery modules 920-1 . . . 920-N. The system 900 includes monitoring electronics 915-1 . . . 915-N attached to battery modules 920-1 . . . 920-N, respectively. The battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N can be implemented in a number of apparatus that use one or more battery modules with each battery module having one or more batteries. The monitoring electronics 915-1 . . . 915-N can be used in testing battery modules 920-1 . . . 920-N, as taught herein. Data collected by the monitoring electronics 915-1 . . . 915-N can be used to keep track of SOC, SOH, voltage parameters, temperature, or combinations thereof of the battery modules 920-1 . . . 920-N or one or more batteries contained in the battery modules 920-1 . . . 920-N. The battery modules 920-1 . . . 920-N and the monitoring electronics 915-1 . . . 915-N can be implemented in electric vehicles, vehicles having a battery-based electric function, or other apparatus. A vehicle can include a truck, a bus, a ship, an airplane, a bike, a robot, a train, or other instrumentality that moves as part of its function.

System 900 can be a networked system in which the battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N, respectively, can be located in a manufacturing storage region after testing of the battery modules 920-1 . . . 920-N or in an apparatus powered by one or more batteries. The battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N can be implemented similar to battery module 120 having monitoring electronics of FIG. 4 or battery module 920-j, j=1, 2, . . . 8 having monitoring electronics of FIG. 7 , but not limited to eight battery modules.

System 900 may also include a number of components such as one or more processors 952, memory module 955, communications unit 958, data processing unit 954, electronic apparatus 954, peripheral devices 957, display unit(s) 961, user interface 962, and selection device(s) 964. The one or more processors 952 may operate as a single processor or a group of processors. Processors of the group of processors may operate independently depending on an assigned function. One or more processors 952 can be realized in one or more application-specific integrated circuits (ASICs). One or more processors 952 may be realized in one or more digital signal processors (DSPs). In controlling operation of the components of system 900 to execute schemes associated with the functions for which system 900 is designed, one or more processors 952 can direct access of data to and from a database.

System 900 can include one or more processors 952, memory module 955, and communications unit 958 arranged to operate as a processing unit to control management of the battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N. In addition, for example, the one or more processors 952, memory module 955, and communications unit 958 can be arranged to adjust operating parameters of the battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N. Depending on the application, communications unit 958 may use combinations of wired communication technologies and wireless technologies.

Memory module 955 can include a database having information, algorithms, and other data such that system 900 can operate on data from battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N. The database can include information that converts observable data to hidden states. The database can include information that converts impedances generated from modelling to hidden states. Algorithms stored in memory module 955, including algorithms for computations and modeling, can be used to extract SOC, SOH, temperature, and hidden states of the battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N. Theses computation and modeling algorithms can include a number of different known algorithms. Data processing unit 954 can be implemented as a standalone unit to determine SOC, SOH, temperature, and hidden states or data processing unit 954 may be distributed among the components of system 900 including memory module 955 and/or electronic apparatus 954.

Bus 937 provides electrical conductivity among the components of system 900. Bus 937 may include a number of different communication channels. For local use with battery modules 920-1 . . . 920-N, bus 937 may include an address bus, a data bus, and a control bus, where each may be independently configured. Bus 937 may be realized using a number of different communication mediums that allow for the distribution of components of system 900. Use of bus 937 can be regulated by one or more processors 952. Bus 937 may be operable as part of a communications network to transmit and receive signals including data signals and command and control signals. Bus 937 can be implemented as a distributed bus, including a wireless communication link, for overall operation of system 900 having a number of sub-systems.

In various embodiments, peripheral devices 957 may include drivers to provide voltage and/or current output from battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N, additional storage memory, or other control devices that may operate in conjunction with the one or more processors 952 or memory module 955.

Display unit(s) 961 can be arranged with a screen display that can be used with instructions stored in memory module 955 to implement user interface 962 to manage the operation of battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N and/or components distributed within system 900.

Display unit(s) 961 can display information regarding battery modules 920-1 . . . 920-N or one or more batteries contained in these modules, where the information is acquired through monitoring battery modules 920-1 . . . 920-N during relaxation periods of these battery modules. Such information can include, but is not limited to, one or more of an alert of battery degradation, a quality grade of the battery module, and a characterization of health of the battery. Such a user interface can be operated in conjunction with communications unit 958 and bus 937. Display unit(s) 961 can include a video screen or other structure to visually project data/information and images. System 900 can include a number of selection devices 964 operable with user interface 962 to provide user inputs to operate data processing unit 954 or its equivalent. Selection device(s) 964 can include a touch screen or a selecting device operable with user interface 962 to provide user inputs to operate data processing unit 954 or other components of system 900.

System 900 can be implemented as test equipment with battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N being the workpiece on which such test equipment operates. System 900 can be implemented as test equipment such as test equipment 125 of FIG. 3 . System 900 can be implemented, at least in part, in apparatus such as, but not limited to, electric vehicles, vehicles having a battery-based electric function, or other apparatus having off periods of battery use.

One or more of the components of the system 900 can be included in an electric vehicle that is powered by the battery modules 920-1 . . . 920-N having monitoring electronics 915-1 . . . 915-N. The stimulus may be applied to one or more of the battery modules 920-1 . . . 920-N while the vehicle is on, and the stimulus to the battery module may be removed when the vehicle is turned off. In some examples, the stimulus is applied while the vehicle is operating (e.g., being driven or otherwise moving).

According to some examples, the stimulus is applied to the battery modules 920-1 . . . 920-N using a stimulus component of the vehicle. Some examples of a stimulus component include an onboard battery charger of the vehicle and a heater of the vehicle. A processing unit of the vehicle (e.g., a processing unit arranged from one or more processors 952, memory module 955, and communications unit 958) can operate to control the stimulus, removing of the stimulus, and monitoring of the battery during a battery relaxation period. The battery relaxation period can be a time period of one or more minutes to several hours after the stimulus to the battery is removed. The processing unit may be included in a BMS of the vehicle. There may be a separate monitoring component or monitoring process for batteries and battery packs, or the onboard battery charger may include the monitoring component.

In some examples, the processing unit detects a specific condition and applies the stimulus to the battery module of the vehicle in response to detecting the vehicle is in the specific condition. Some examples of a specific condition in which it may be desirable to test the battery module include detecting a specified level of charge on the batteries, detecting a high current draw of one or more batteries, or detecting that the batteries are at a specific temperature. For instance, a battery health evaluation may be triggered by a detected temperature condition, the results of the evaluation may indicate that battery conditioning systems should be turned on to prevent present or further thermal degradation.

In some examples, the processing unit places the vehicle in the specific condition and enables applying the stimulus to the battery module of the vehicle when the vehicle is in the specific condition, or the stimulus can be applied a specified wait time after the vehicle is place in the desired condition. Some examples of placing the car in a specific condition for testing the battery module include initiating a charging sequence for the battery module and applying the stimulus to the battery before the charging, applying the stimulus at a battery rest period programmed into a charging profile of the charging sequence, and applying the stimulus at a specific state of charge of the sequence such as the end of charge sequence.

According to some examples, the stimulus is applied to the battery modules 920-1 . . . 920-N using stimulus equipment external to the vehicle (e.g., external battery test equipment or a fast direct current charger). The processing unit of the vehicle may send a stimulus command to the external stimulus equipment to apply the stimulus to the battery modules 920-1 . . . 920-N, and send an end stimulus command to remove the stimulus to the battery modules 920-1 . . . 920-N. The processing unit may send a signal calling for a specific stimulus to the battery module. The signal is received by the external equipment that may initiate a preconditioning sequence to put the battery in a specific state or condition for health analysis (e.g., a specific temperature and or specific state of charge). The external stimulus equipment applies the specific stimulus when it detects that the appropriate testing conditions are met. The battery response to the stimulus is monitored by the processing unit. The processing unit may then time the battery relaxation period and enable measurements by the monitoring electronics 915-1 . . . 915-N. After the monitoring period, the processing unit may display a characterization of health of the battery.

According to some examples, a second stimulus is applied to the battery modules 920-1 . . . 920-N. The second stimulus may be applied to the battery modules after turning off use of the battery module and prior to the post-stimulus battery relaxation period. The second stimulus is removed, and data is collected by the monitoring electronics 915-1 . . . 915-N during the post-stimulus battery relaxation period.

The second stimulus can be applied differently from how the first stimulus is applied. In some examples, the second stimulus is applied using different wiring from the equipment applying the first stimulus. In some examples, one of the stimuli (either the first stimulus or the second stimulus) is applied as a current source and the other of the stimuli is applied via one or more bleed resistors.

In some examples, the peak power of the second stimulus is far smaller than the peak power of the first stimulus (e.g., the second stimulus can include current an order of magnitude smaller than current of the first stimulus). This allows the second stimulus to be generated by test equipment that is small enough or cheap enough to be embedded with the battery modules 920-1 . . . 920-N or battery monitoring electronics 915-1 . . . 915-N and to travel with the battery module. In some examples, the first stimulus is generated using a stimulus component of test equipment external to the battery modules 920-1 . . . 920-N while the second stimulus is generated internally to the battery modules 920-1 . . . 920-N by embedded electronics (e.g., a stimulus component of monitoring electronics 915-1 . . . 915-N).

EIS characteristics of the battery module or the one or more of the batteries can be calculated based on data from the recorded signals and one or both of the stimuli applied to the battery modules. Electro-mechanical characteristics may be calculated as well. For example, the battery modules can include battery bus bars that are used in interconnection of the batteries. Fast charging of the batteries and heavy loads on the battery modules can heat up the bus bars causing expansion and mechanical stress. This can become a problem if the heating causes the bus bars to become loose or distorted. Changes the bus bars and other interconnection structures can be detected using EIS information.

A battery health monitoring protocol may involve the measurement of individual variables, those variables over time, or the variables over time in response to, or a given time away from, a stimulus or specific condition being met. For instance, Electrochemical Impedance Spectroscopy (EIS) is an impedance measurement that can involve the time correlation of two or more variables with respect to each other (e.g., the difference in response between voltage and current). The measured variables may be integrated from the internal and external systems.

The following are example embodiments of systems and methods of operation, in accordance with the teachings herein.

Example 1 includes subject matter (such as a method of battery testing) comprising applying a stimulus to a battery module, the battery module having one or more batteries; turning off use of the battery module including removing the stimulus to the battery module; after turning off use of the battery module, autonomously recording signals from the battery module during a post-stimulus battery relaxation period using monitoring electronics attached to the battery module; and outputting the recorded signals from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.

In Example 2, the subject matter of Example 1 optionally includes applying the stimulus to the battery module by at least one of charging the battery and discharging the battery.

In Example 3, the subject matter of one or both of Examples 1 and 2 optionally includes applying an alternating current (AC) signal to the battery module; and autonomously recording signals from the battery module includes recording current of the one or more batteries.

In Example 4, the subject matter of one or any combination of Examples 1-3 optionally includes calculating Electrochemical Impedance Spectroscopy characteristics of the one or more of the batteries based on data from the recorded current and the stimulus.

In Example 5, the subject matter of one or any combination of Examples 1-4 optionally includes applying the stimulus to the battery module includes applying the stimulus to a battery module of a vehicle while the vehicle is on; and turning off use of the battery module including removing the stimulus to the battery module includes removing the stimulus to the battery module when the vehicle is turned off.

In Example 6, the subject matter of Example 5 optionally includes applying the stimulus to the battery module of the vehicle when detecting that the battery module is at a predetermined temperature.

In Example 7, the subject matter of one or both of Examples 5 and 6 optionally includes placing the battery module in a specified charge condition and applying the stimulus to the battery module of the vehicle when the battery module is in the specified charge condition.

In Example 8, the subject matter of one or any combination of Examples 5-7 optionally includes applying the stimulus to the battery module using a stimulus component of the vehicle.

In Example 9, the subject matter of Example 8 optionally includes applying the stimulus to the battery module using one of an onboard battery charger of the vehicle or a heater of the vehicle.

In Example 10, the subject matter of one or any combination of Examples 1-9 optionally includes applying the stimulus to the battery module includes applying the stimulus to a battery module of a vehicle using test equipment external to the vehicle in response to a command from a battery management system (BMS) of the vehicle; and turning off use of the battery module including removing the stimulus to the battery module includes removing the stimulus to the battery module in response to another command from the BMS of the vehicle.

In Example 11, the subject matter of one or any combination of Examples 1-10 optionally includes applying a second stimulus to the battery module after the turning off use of the battery module and prior to the post-stimulus battery relaxation period; and removing the second stimulus and autonomously recording the signals from the battery module during the post-stimulus battery relaxation period.

In Example 12, the subject matter of one or any combination of Examples 1-11 optionally includes applying the second stimulus to the battery module using a stimulus circuit included in the monitoring electronics of the battery module and applying the previous stimulus using test equipment external to the battery module.

Example 13 includes subject matter (such as a system) or can optionally be combined with one or any combination of Examples 1-12 to include such subject matter, comprising a battery module having one or more batteries; monitoring electronics attached to the battery module, the monitoring electronics to monitor response of a battery of the battery module to a stimulus applied to the battery; and a controller. The controller is configured to perform operations that include turning off use of the battery module including removing the stimulus to the battery module; after removing the stimulus to the battery module, timing a post-stimulus battery relaxation period and autonomously recording signals from the battery module during the post-stimulus battery relaxation period using the monitoring electronics; and outputting the recorded signals from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.

In Example 14, the subject matter of Example 13 optionally includes a stimulus component configured to apply the stimulus to the battery by charging the battery.

In Example 15, the subject matter of one or both of Examples 13 and 14 optionally includes applying a stimulus to a battery module includes applying an alternating current (AC) signal to the battery module; and autonomously recording signals from the battery module includes recording current of the one or more batteries.

In Example 16, the subject matter of one or any combination of Examples 13-15 optionally includes calculating Electrochemical Impedance Spectroscopy characteristics of the one or more of the batteries based on data from the recorded current and the stimulus.

Example 17 includes subject matter (such as an electric vehicle) or can optionally be combined with one or any combination of Examples 1-16 to include such subject matter, comprising a battery module having one or more batteries to power the electric vehicle; monitoring electronics attached to the battery module, the monitoring electronics to monitor response of a battery of the battery module to a stimulus applied to the battery; and a controller. The controller is configured to perform operations including turning off use of the battery module including removing the stimulus to the battery module; after removing the stimulus to the battery module, timing a post-stimulus battery relaxation period and autonomously recording signals from the battery module during the post-stimulus battery relaxation period using the monitoring electronics; and outputting the recorded signals from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.

In Example 18, the subject matter of Example 17 optionally includes a stimulus component configured to apply the stimulus to the battery module of the vehicle; and a controller configured to enable the stimulus to the battery by the stimulus component when the vehicle is on and enable recording signals from the battery module when the vehicle is off.

In Example 19, the subject matter of Example 18 optionally includes the stimulus component being one of an onboard battery charger or a heater of the vehicle.

In Example 20, the subject matter of one or any combination of Examples 17-19 optionally includes a stimulus component configured to apply the stimulus to the battery module of the vehicle; and a controller configured to enable the stimulus to the battery by the stimulus component when the vehicle is moving and enable recording signals from the battery module when the battery module is in an off-status.

In Example 21, the subject matter of one or any combination of Examples 17-20 optionally includes a controller configured to detect when the battery module is in a specified charge condition and enable the applying the stimulus to the battery module of the vehicle in response to detecting that the battery module is in the specified charge condition.

In Example 22, the subject matter of one or any combination of Examples 17-21 optionally includes a controller configured to send a command to separate test equipment to apply the stimulus to the battery module; and send another command to the test equipment to remove the stimulus to the battery; and enable the autonomously recording signals from the battery module in response to sending the other command.

The above detailed description refers to the accompanying drawings that show, by way of illustration and not limitation, various embodiments that can be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice these and other embodiments. Other embodiments may be utilized, and structural, logical, mechanical, and electrical changes may be made to these embodiments. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The above detailed description is, therefore, not to be taken in a limiting sense.

Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. Various embodiments use permutations and/or combinations of embodiments described herein. It is to be understood that the above description is intended to be illustrative, and not restrictive, and that the phraseology or terminology employed herein is for the purpose of description. 

What is claimed is:
 1. A method of battery testing, the method comprising: applying a stimulus to a battery module, the battery module having one or more batteries; turning off use of the battery module including removing the stimulus to the battery module; after turning off use of the battery module, autonomously recording signals from the battery module during a post-stimulus battery relaxation period using monitoring electronics attached to the battery module; and outputting the recorded signals from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.
 2. The method of claim 1, wherein applying the stimulus to the battery module includes at least one of charging the battery and discharging the battery.
 3. The method of claim 1, wherein applying a stimulus to a battery module includes applying an alternating current (AC) signal to the battery module; and autonomously recording signals from the battery module includes recording current of the one or more batteries.
 4. The method of claim 3, wherein the method includes calculating Electrochemical Impedance Spectroscopy characteristics of the one or more of the batteries based on data from the recorded current and the stimulus.
 5. The method of claim 1, wherein applying the stimulus to the battery module includes applying the stimulus to a battery module of a vehicle while the vehicle is on; and turning off use of the battery module including removing the stimulus to the battery module includes removing the stimulus to the battery module when the vehicle is turned off.
 6. The method of claim 5, wherein applying the stimulus to the battery module of the vehicle includes applying the stimulus to the battery module of the vehicle when detecting that the battery module is at a predetermined temperature.
 7. The method of claim 5, wherein applying the stimulus to the battery module of the vehicle includes placing the battery module in a specified charge condition and applying the stimulus to the battery module of the vehicle when the battery module is in the specified charge condition.
 8. The method of claim 5, wherein applying the stimulus to the battery module includes applying the stimulus to the battery module using a stimulus component of the vehicle.
 9. The method of claim 8, wherein applying the stimulus to the battery module using a stimulus component of the vehicle includes applying the stimulus to the battery module using one of an onboard battery charger of the vehicle or a heater of the vehicle.
 10. The method of claim 1, wherein applying the stimulus to the battery module includes applying the stimulus to a battery module of a vehicle using test equipment external to the vehicle in response to a command from a battery management system (BMS) of the vehicle; and turning off use of the battery module including removing the stimulus to the battery module includes removing the stimulus to the battery module in response to another command from the BMS of the vehicle.
 11. The method of claim 1, including: applying a second stimulus to the battery module after the turning off use of the battery module and prior to the post-stimulus battery relaxation period; and removing the second stimulus and autonomously recording the signals from the battery module during the post-stimulus battery relaxation period.
 12. The method of claim 11, wherein applying the second stimulus includes applying the second stimulus to the battery module using a stimulus circuit included in the monitoring electronics of the battery module and applying the previous stimulus using test equipment external to the battery module.
 13. A system comprising: a battery module having one or more batteries; monitoring electronics attached to the battery module, the monitoring electronics to monitor response of a battery of the battery module to a stimulus applied to the battery; and a controller configured to perform operations, the operations including: turning off use of the battery module including removing the stimulus to the battery module; after removing the stimulus to the battery module, timing a post-stimulus battery relaxation period and autonomously recording signals from the battery module during the post-stimulus battery relaxation period using the monitoring electronics; and outputting the recorded signals from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.
 14. The system of claim 13, including a stimulus component configured to apply the stimulus to the battery by charging the battery.
 15. The system of claim 13, wherein applying a stimulus to a battery module includes applying an alternating current (AC) signal to the battery module; and autonomously recording signals from the battery module includes recording current of the one or more batteries.
 16. The system of claim 13, wherein the method includes calculating Electrochemical Impedance Spectroscopy characteristics of the one or more of the batteries based on data from the recorded current and the stimulus.
 17. An electric vehicle comprising: a battery module having one or more batteries to power the electric vehicle; monitoring electronics attached to the battery module, the monitoring electronics to monitor response of a battery of the battery module to a stimulus applied to the battery; and a controller configured to perform operations, the operations including: turning off use of the battery module including removing the stimulus to the battery module; after removing the stimulus to the battery module, timing a post-stimulus battery relaxation period and autonomously recording signals from the battery module during the post-stimulus battery relaxation period using the monitoring electronics; and outputting the recorded signals from which one or more electrochemical parameters or one or more electrical parameters of the battery module or the one or more batteries arranged in the battery module are calculated using the recorded signals.
 18. The electric vehicle of claim 17, including: a stimulus component configured to apply the stimulus to the battery module of the vehicle; wherein the controller is configured to enable the stimulus to the battery by the stimulus component when the vehicle is on and enable recording signals from the battery module when the vehicle is off.
 19. The electric vehicle of claim 18, wherein the stimulus component is one of an onboard battery charger or a heater of the vehicle.
 20. The electric vehicle of claim 17, including: a stimulus component configured to apply the stimulus to the battery module of the vehicle; wherein the controller is configured to enable the stimulus to the battery by the stimulus component when the vehicle is moving and enable recording signals from the battery module when the battery module is in an off-status.
 21. The electric vehicle of claim 17, wherein the controller is configured to detect when the battery module is in a specified charge condition and enable the applying the stimulus to the battery module of the vehicle in response to detecting that the battery module is in the specified charge condition.
 22. The electric vehicle of claim 17, wherein the controller is configured to: send a command to separate test equipment to apply the stimulus to the battery module; send another command to the test equipment to remove the stimulus to the battery; and enable the autonomously recording signals from the battery module in response to sending the other command. 